W Minz R, Bakshi A, Chhabra S, Joshi K, Sakhuja V
Department of Immunopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Indian J Nephrol. 2010 Jan;20(1):34-9. doi: 10.4103/0971-4065.62098.
The aim was to evaluate the role of a-smooth muscle actin (SMA) and collagen type IV as markers of chronicity in renal biopsies of IgA nephropathy patients and to correlate the degree of their interstitial expression with renal function as judged by serum creatinine. Renal biopsies from 29 clinically, histologically and immunologically confirmed cases of IgA nephropathy were reviewed to assess activity and chronicity indices. Immunohistochemical stains for alpha-SMA and collagen type IV was performed on 23 patients with adequate tissue available in the block. The interstitial expression of alpha-SMA and collagen type IV was then correlated with chronicity and activity indices, serum creatinine and 24 hours urinary protein. Pearson's coefficient of correlation, unpaired-t test were used for statistical analysis. alpha-SMA and collagen type IV were shown to be expressed in the interstitium in all 22 cases showing interstitital fibrosis. Both showed a similar distribution pattern with predominant periglomerular and peritubular positivity. The cases were divided into two groups (low and high grade) depending on the percentage of interstitial area showing positivity for these two antibodies. On statistical analysis, the expression of both a-smooth muscle actin and collagen type IV showed a striking correlation with the histological chronicity index (P<0.01). A positive correlation was also noted with the serum creatinine at the time of diagnosis. It is seen that an immunohistochemical approach to grading interstitial fibrosis as in this study is far simpler than the histological grading systems prevalent and is an important baseline prognostic indicator.
目的是评估α-平滑肌肌动蛋白（SMA）和IV型胶原作为IgA肾病患者肾活检中慢性病变标志物的作用，并将它们的间质表达程度与血清肌酐判断的肾功能进行关联。回顾了29例经临床、组织学和免疫学确诊的IgA肾病患者的肾活检标本，以评估活动度和慢性病变指数。对23例在组织块中有足够可用组织的患者进行了α-SMA和IV型胶原的免疫组织化学染色。然后将α-SMA和IV型胶原的间质表达与慢性病变和活动度指数、血清肌酐及24小时尿蛋白进行关联。采用Pearson相关系数、非配对t检验进行统计分析。在所有22例显示间质纤维化的病例中，α-SMA和IV型胶原均在间质中表达。两者显示出相似的分布模式，主要为肾小球周围和肾小管周围阳性。根据这两种抗体阳性的间质面积百分比，将病例分为两组（低级别和高级别）。经统计分析，α-平滑肌肌动蛋白和IV型胶原的表达均与组织学慢性病变指数显著相关（P<0.01）。在诊断时与血清肌酐也呈正相关。可见，如本研究中采用免疫组织化学方法对间质纤维化进行分级远比普遍使用的组织学分级系统简单，且是一个重要的基线预后指标。
